The present invention relates to an ice-breaking apparatus for a structure for use in icy waters.
With recent increase of demand for energy sources and because of uneven distribution of petroleum resources and rise in prices of petroleum products, the importance of exploitation of submarine oil resources has been increasing, and even icy water regions are now objects of this exploitation. The exploitation of submarine oil resources involves a serious problem; how to protect an oil-drilling structure, for example, an oil-drilling platform, from external forces of floating ice lumps or floes surging upon the structure.
In order to cope with this problem, the configuration or framework of the structure has heretofore been especially arranged or designed as shown in FIGS. 7-(a) to 7-(h) of the accompanying drawing, but in many cases, no sufficient ice-breaking capacity can be obtained. Therefore, the operation region or time is often restricted.
The present invention is to overcome this defect involved in the conventional techniques. It is therefore a primary object of the present invention to provide an ice-breaking apparatus in which ice lumps are positively broken to reduce external forces imposed on an oil-drilling structure without adopting negative means of improving the ice-resisting capacity by changing the configuration of the structure.
Another object of the present invention is to provide an ice-breaking apparatus in which ice lumps are broken mainly by utilizing the flexural load.
Still another object of the present invention is to provide an ice-breaking apparatus which can be operated any time and anywhere with restrictions on the operation time and region being completely removed.